1. Field of the Invention
The present invention relates to cap-and-base type pneumatic tires provided with two rubber layers composed of a non-foamed rubber and a foamed rubber, respectively, in a tread portion.
2. Related Art Statement
A variety of pneumatic tires have been proposed, which have excellent performance on ice and snow roads (hereinafter referred to as "ice and snow performance"). That is, they exhibit excellent driving performance, braking performance and cornering stability during running on ice and snow roads and which can prevent occurrence of dust during running on dry roads. For example, a pneumatic tire having a foamed rubber layer containing closed cells and arranged in a treading surface portion of a tread is known.
However, since the treading surface portion of the tread of such a conventional pneumatic tire is entirely constituted by a foamed rubber having low rubber hardness (low rigidity), the treading surface portion is largely deformed during running under load. As a result, the tire has a problem in that the tread portion of the tire is worn out at an early stage through running on dry roads.